The textile filaments are generally subjected, before their use, particularly for weaving, to washing and/or bleaching treatments as well as dyeing.
To this end, the dyeing is particularly carried out in moist condition by means of machines with one or several application stations, which are traversed by the filaments of a layer of filaments to be died.
In known application stations, particularly from FR-A-2 650 311 and FR-A-2 693 486, as well as U.S. Pat. Nos. 5,339,658 and 5,594,968, the filaments are subjected to successive impregnations by spots, commonly called "spaced dyeing" by cyclic or semi-random interruption of the application of the dyestuff.
Such an interruption can be carried out by acting on the means for supplying the dyebath, namely by provision of an applicator of the turbine type delivering radial jets or an application with contact rollers co-acting with rotatable means for cyclic or semi-random application of the filaments to said rollers, or else by a provision of an applicator of the nozzle type co-acting with the movable closure member, for example in the form of a disc provided with at least one calibrated slot for passage of the dyestuff. This latter embodiment is particularly known from FR-A-2 719 058.
Machines provided with application heads generally satisfy all the requirements of quality. However, their treatment capacity is limited, either to a number of filaments corresponding in width to a layer formed at the maximum length of the closure member, in the case of an applicator of the nozzle type co-acting with a movable closure member in the form of a disc provided with at least one calibrated slot, or to a maximum speed of movement of the filaments, in the case of application by contact with contact rollers co-acting with rotatable means for cyclic application of the filaments against said rollers, because of the inertia of the rotatable actuators.
As a result, an increase in output is not possible except by increasing the internal volume of the application heads. Such a solution is however not suitable, for obvious reasons of the size of the application heads involving the corresponding over-dimensioning of the assembly of the machine.
Thus, the processes and devices for dyeing by application of spots, commonly called "spaced dyeing", do not permit the provision of spots of relatively short length except by changing the speed of movement of the filaments, compensating the inertia of the cyclic closure means for application of the dyestuff, or the rotatable actuators of the rotatable means for cyclic application of the filaments against the contact rollers.